There are two general categories of motor vehicle wheel end assemblies: dead spindle and live spindle. Dead spindle wheel end assemblies generally include a non-rotatable spindle extending outward from a mounting member typically attached to a vehicle chassis. A wheel hub including a wheel mounting flange, is supported for rotation on the spindle by bearings. A wheel and tire assembly are then attached to the wheel mounting flange so that the wheel is mounted coaxially with the spindle and wheel hub.
Live spindle wheel end assemblies generally include a spindle that is supported for rotation by bearings within a bore formed in a mounting member such as a steering knuckle which is attached to the vehicle chassis. A wheel mounting flange is formed in the spindle or is secured thereto by welding or other suitable methods. To provide the live spindle wheel end assembly for use of a four-wheel drive vehicle, a bore is formed through the spindle to accept a drive axle.
The central tire inflation system is adapted to provide compressed air from a remote pressurized air source to a pneumatic tire of a motor vehicle. Since the tire is rotating and the pressurized air source is stationary, the typical tire inflation system includes some kind of sealing means located between a stationary member of the wheel end assembly and a rotating tire mounting spindle. The typical tire inflation system also is provided with a conduit that extends from the sealing means through the wheel end assembly to the pneumatic tire. It has been found particularly difficult to design the tire inflation system for live spindle wheel ends wherein pressurized air is transmitted from the fixed inflation air source to pneumatic tires mounted on steering wheels of a drive axle.
Current systems are quite complex, cumbersome, expensive and require a great deal of changes in the current production wheel end design.